The present invention relates to an apparatus and method for automated machining and welding of railway car parts, including side frames and bolsters, useful in connection with both manufacturing and reconditioning of such parts.
Current processes for manufacturing and reconditioning freight car side frames and bolsters involve intensive manual labor inputs. A conventional “hard” gauge made of precision steel is used to determine variance of a part from desired dimensions, and specially trained workers manually weld and grind the cast part to desired finished sizes and dimensions. Conventional gauges use generous tolerances, which in turn produce railway parts with minimal dimensional accuracy, resulting in poor truck assembly performance. Furthermore, the manual work presents a high risk of injury to workers, and high expense to employers having to sustain a trained workforce and provide compensation for risky activities and/or possible injuries.
Moreover, remanufacturing side frames and bolsters involves concentrating dedicated equipment and specialized expertise in a single location. Thus, transportation costs of delivering heavy railway car truck parts to a single location have made the commercial reconditioning processes economically unfeasible. Therefore, a portable system for these purposes would be desirable. However traditional machining (which refers herein to cutting metal with a tool so as to afford greater dimensional accuracy compared to grinding), generally requires secure mounting of the very large and heavy machinery to the ground to control vibration. Thus, designing a portable system for machining large, heavy parts with computer controlled robots poses significant challenges.
Further, using a physical gauge to compare and conform one surface of a railcar part to another limits the comparison to surfaces that are near each other. It would be desirable to leverage different dimensional reference points on a railway car part, such as a side frame or bolster, with the ability to compare and conform surfaces that are more distant to one another.
U.S. Pat. No. 4,187,600, incorporated by reference, teaches an apparatus for machining railroad truck bolsters, which includes a rotatable fixture for supporting a bolster while it is worked on. U.S. Pat. No. 4,190,390 to the same inventor, also incorporated by reference, discloses an apparatus for machining railroad truck side frames.
Although not heretofore used in connection with reconditioning railcar truck parts, robot positioning systems are known that use six jacks to rotate a tool about six axes: the x, y, z, pitch, roll and yaw axes. In various embodiments, these positioning systems are referred to as hexapods or Stewart platforms. Examples include the technology disclosed in U.S. Pat. Nos. 6,071,031 and 6,240,799, which are incorporated by reference. A hexapod, or the like apparatus, heretofore has not been used with combined welding and machining of large and heavy cast parts, such as a railway car side frame.
US Patent Application Publication No. US/2004/0014405, also incorporated by reference, describes a portable machining device used to reprofile wheels through lathing, broaching, milling, turn milling, grinding, and deep rolling operations without detaching the wheels from the railway car.
US 2015/0034607 and US 2010/161123, also incorporated by reference, disclose robots and systems for controlling them, which may be applied to certain welding applications.
US 2011/0174793, also incorporated by reference, describes a robot system having a positioner allowing for mobility and reduced footprint. U.S. Pat. No. 5,783,921, also incorporated by reference, describes a welding robot adapted for simplified installation and operation.
The prior art does not teach an automated system for initial inspection, welding, material removal and final part inspection for railway car truck parts that uses a hexapod robot on a rail system, or which can be transported from one installation location to another, or that leverages novel dimensional reference surfaces on the parts to improve overall tolerances and truck performance.